Method of making porous fibrous sheet material



June 26, 1962 R. e. RUSSELL 3,040,412

METHOD OF MAKING POROUS ,FIBROUS SHEET MATERIAL Original Filed July 9,1956 4 Sheets-Sheet 1 .I Ell INV EN TOR.

ROBERT GI Passe-1.1.

ATTORNEYS June 26, 1962 R. cs. RUSSELL 3,040,412

METHOD OF MAKING POROUS FIBROUS SHEET MATERIAL Original Filed July 9,1956 4 Sheets-Sheet 2 v INVENTOR. ROBERT 61 Russsu.

June 26, 1962 R. e. RUSSELL 3,040,412

METHOD OF MAKING POROUS FIBROUS SHEET MATERIAL 4 Sheets-Sheet 3 OriginalFiled July 9, 1956 INVENTOR. Roam-r 6. RUSSELL 6 m .19. 1 FL A X :41 m"A .21 6 Mb kw m x 47 TORNE K5 June 26, 1962 R. G. RUSSELL 3,040,412

METHOD OF MAKING POROUS FIBROUS SHEET MATERIAL 4 Sheets-Sheet 4 OriginalFiled July 9, 1956 INVENTOR. ROBERT 6. RUSSELL 4T TOR/VfYS United StatesPatent @fiioe 3,940,412 Patented June 26, 1962 3,040,412 METHOD OFMAKING POROUS FIBROUS SHEET MATERIAL Robert G. Russell, Granville, Ohio,assignor to Owens- Corning Fiberglas Corporation, a corporation ofDelaware Original application July 9, 1956, Ser. No. 596,490, now PatentNo. 2,981,999, dated May 2, 1961. Divided and this application June 8,1960, Ser. No. 41,713

3 Claims. (Cl. 28-72) This application is a division of applicationSerial No. 596,490, now Patent No. 2,981,999 issued on May 2, 1961, inthe name of the present inventor.

This invention relates to a method and apparatus for producing a newtype of nonwoven sheet material or mat and more particularly to nonwovensheets or mats made of fibrous glass.

It is conventional practice to incorporate in nonwoven sheets or matsmade of fibrous matter, a bonding agent to effect joinder of the fibersinto an integrated mass. The binder material incorporated in the productusually bonds the fibers at their points of intersection and therebycauses it to acquire a dimensionally stable form. Binder materials haveheretofore been considered quite necessary in the manufacture ofnonwoven fabrics or mats, especially when the product is made ofmaterial such as "glass fibers and filaments whichcharacteristicallyhave smooth nonprojecting or nontentacle'd surfaces which do not lendthemselves to establishment of a clinging or grasping interconnectingrelationship.

Bonding materials in many instances, however, are undesirable because oftheir possible incompatibility with material subsequently to beincorporated with products to be produced. For example, because of thegreat strength of glass fibers they are frequently utilized in themanufacture of mats and fabrics which are subsequently incorporated inproducts such as articles molded of resinous material, as well as othermaterials, both organic and inorganic, including materials such asmetal. The strength of glass fibers in such instances is extremelyvaluable in imparting strength as reinforcement to a basic matrixmaterial. Frequently the material to be so reinforced wi'll not wet outthe fabric or mat when certain binder materials are incorporatedtherein, or when a percentage of binder material is incorporated thereinbeyond a certain limit. Still further, binding materials incorporated inglass fabrics or mats are often not compatible with the material thus tobe reinforced, and accordingly it would frequently be desirable if themat or fabric would have an inherent integrity of its own which would doaway with the need for a binding agent altogether.

Accordingly, it is an object of this invention to provide a new methodand means for producing a mat or fabric of fibrous material which willdo away with the need for binder material to impart the desiredintegrity to the product.

Another object of the invention is to provide a method and means formanufacture or production of mats and fabrics of fibrous materialwithout a binding agent incorporated therein, and in the process ofproduction, to treat the basic material of the product to make it morereadily adaptable to .subsequent processing.

It is still another object of the present invention/to provide a methodfor producing a new fibrous glass mat or fabric of nonwoven characterwhich is adaptable to manufacture on conventional production equipment.

In brief, the invention is related to the production of binderless matsor nonwoven fabrics by accumulating material in fibrous form as a massand then subjecting such mass to gaseous blasts to cause aninterengagin-g relationship or interlocking association of portions offibers thereof to provide the integrity desired. In other words, a layerof fibers either discontinuous or continuous when subjected to theforces of gaseous blasts directed immediately thereagainst according tothis invention causes fibers to inter-engage each other at the exposedsurface of the layer as well as extend from the surface of the layer tointernal parts of the mat, thereby causing the fibers themselves to actas interlocking bonding elements.

Other objects and features which I believe to be characteristic of myinvention are set forth with particularity in the appended claims. Myinvention, however, both in organization and manner of constructiontogether with further objects and advantages thereof may be best understood by reference to the following description taken in connectionwith the accompanying drawings, in which:

FIGURE 1 is a partially schematic side elevational view of a productionline with two forming stages for manufacture of fibrous mats accordingto the present invention;

FIGURE 2 is an enlarged view in perspective of a single forming stage ofthe type incorporated in the production line of FIGURE 1;

FIGURE 3 is an illustration representative of a section of mat ofcontinuous fiber strands made according to the present invention;

FIGURE 4 is a side elevational view of another arrangernent of apparatusfor forming mats according to the present invention;

FIGURE 5 is a perspective view of a process for subjecting mats totreatment for embossed designs according to the present invention;

FIGURE 6 is a top plan view of a conveyor belt with apertured designscapable of being impressed in embossed form on mats treated according tothis invention; and

FIGURE 7 is a side elevational view of another arrangement of apparatusfor treatment of mats according to the present invention.

Although the mats made according to this invention are capable ofbeingproduced from any of a variety of materials including resinous andmineral materials, their production is herein described in relation toformation of fibers of materials such as glass because of itsadaptability to production at extremely high rates of speed.

Turning to the drawings in greater detail wherein identical referencenumerals are used in referring to similar parts, FIGURE 1 shows acomplete production line for the manufacture of continuous strand matsincluding two similar stages of strand and mat formation which arearranged in tandem relationship along the length of the line. The twostages of formation comprise a first stage which deposits a bottomstrand layer 31 on the conveyor while the second stage deposits a toplayer 31' thereover to make up a mat product.

When the material of which the mats are made is glass, as hereindescribed, it may be initially in the form of marbles supplied from acommon source 10 through supply chutes 11. Fronr the chutes the marblesare introduced into melting units of both stages of fiber formation. Themelting apparatus in each stage consists of a pair of electrical meltingunits 12 and 12' and associated feeders 13 and 13, respectively. Theglass is attenuated into filaments 14 and 14' from the feeders 13 and13', respectively. Each group of filaments 14 is drawn over a roll-typesizing applicator l6 and 16' before being gathered into the form ofstrands 20 and 20' over gathering members 18 and 18', respectively.

The sizing material applied tothe filaments may merely be water toprovide the lubricity required at the gathering members 18 and 18'. Suchsizing material later evaporates or can be dried leaving only the bareglass filaments in the strand. A sizing fluid isfrequently. desirable,however, which will leave. a coating-on the strand to promote inutegrity in the strand as well as to promote compatibility with othermaterials in further production operations. For example, it might bedesirable to incorporate a sizing fluid in the strand which will promotewetting of the mat by a resin which the mat is to reinforce in a finalproduct.

As may be seen more clearly in FIGURE 2 the strands 20 and 26 are drawnthrough a guide eye 21 by a single pair of mated pulling wheels 2. Thestrands are pulled in the same general direction in spaced relation andare imparted suflicient kinetic energy that when driven against alaterally oscillating deflector unit 24 they are deflected and depositedin intermixed relation as an accumulation 33 on a conveyor belt 35 whichextends and passes under an overhanging flight formed of a foraminousmesh-type belt 26 inclined downwardly toward the conveyor 35. Ifdesired, the strands can be arranged to have their filaments dispersedin spaced relationship upon impingement against units 24 to impart afiner or fuzzed texture thereto.

The overhanging flight or belt 26 is driven in the same linear directionas the conveyor 35 to cause a compaction of the accumulation 33 underthe flight section beneath the rolls 27 and 36. The overhanging belt 26is as wide as the conveyor belt 35 on which the strand is deposited andis supported by an upper roll 29 and a pair of for-v wardly locatedlower level rolls 27 and 3d spaced from each other and disposed a slightdistance above the conveyor. The rolls 27 and 30 are adjustable up anddown to permit adjustment for the degree of compaction desired to beexercised on the material deposited on the conveyor.

A suction box 37 extends under each stage of formation of the mat andaids compaction of the strand under the overhanging flight 26. Afterpassage under the overhanging flight, the layers 31 and 31 are eachsubjected to the forces of pressurized blasts emitted from blowers 32and 32. The pressurized blasts emitted from the blowers may be any of anumber of gases including air, steam, or treating gases which arecompatible with glass fibers or coatings thereof; or gases which areadvantageously applicable to glass to promote improved properties. Thiscauses some of the relatively loose accumulations of mat, even thoughalready somewhat compacted, to inter-engage both at the surfaces andimmediately below the surfaces of the mat while other portions arepushed downwardly for a frictional inter-engaging relationship withfiber portions located in the interior of the mat.

Each of the layers of mat 31 and 31 are subjected to the forces ofgaseous jets following emission from under the overhanging flights 26and 26, respectively. After formation of the first layer and subjectionthereof to the gaseous blasts of the blower 32, the second layer ofstrand is deposited thereover and the combination of the alreadyintra-knit accumulation 31 and the overlaying accumulation 31' arepassed under the second overhanging flight 26' whereupon the combinationis subjected to a second application of gaseous blast forces from ablower 32. This second application of force by Way of gaseous jetscauses an inter-engagement of portions of the strands and fibers of theoverlying layer 31' within itself as well as with strand and fiberportions of the first layer 31. In another sense, the second stage ofapplication of gaseous blast forces results in an integration of thesecond layer 31 and an inter-knitting thereof with the alreadyintegrated first layer 31 to produce a composite of the two layers whichis effectively a single unitary mat. Experience has indicated that thetwo layers can be. integrated in this manner without tendencies in thefinal product toward separation of the layers.

Although a relatively thick single layer of strand accumulation can beformed into an integral binderless mattype product, a much thickerintegral binderless mat can be produced by joining two layers or more offibrous strand accumulated on top of each other, each being subjected tointegrating forces prior to deposition of another layer thereover. Allthat is required is that the top-most accumulation is not so thick thatthe forces of gaseous jets directed thereagainst cannot reach throughthe entire layer subjected to the forces. That is, the thickness of thetop-most layer must be sufliciently thin that the forces of gaseous jetsdirected thereagainst can extend from the top-most portions of thefibrous layer into the underlayer on which each is deposited.

After being so accumulated and integrated, a strand mat has sufficientintegrity and dimensional stability that it may be rolled up forsubsequent use or processing into a fabricated product. If desired,however, the mat may be passed through a fog chamber 43 for receipt ofmaterials of special nature adaptable to promotion of further processingaccording to customer needs. At this stage a small amount of bindermaterial can be optionally incorporated into the mat to effectastiffening or even a more positive binding of portions of the fiberscontacting each other within the mat. Under these circumstances thematerial to be incorporated in the mat may be injected into the chamber43 in the form of a fog by way of a supply jet 44 and can be arranged tobe drawn through the interior portions of the mat by way of a suctionchamber 45) located under the. foraminous conveyor 35 in the zone belowthe fog chamber 4-3. It is to be understood, however, that this fogchamber treatment is not a necessity in producing the mat according .tothis invention, but that the production of the binderless mat asdescribed lends itself to subsequent incorporation of materials withinthe mat for special purposes depending upon subsequent processing orultimate use of the mat product.

If the mat product is to have matter supplied thereto, such as in theform of a vaporized solution of a resin introduced into the fog chamber43, it can be subsequently cured within an oven 46, if necessary.Subsequent to passage through the oven 46 the product may be passedbetween a pair of cooling rolls 52 and then finally rolled into aroll-type package 59 on roll-up apparatus 60 to make the product readyfor shipment as well as for further processing or fabrication.

Now having described the apparatus and operation of the production lineof FIGURE 1 generally, the first stage of strand deposition is referredto in FIGURE 2 for a more detailed description of the method of formingthe mat-type product of this invention. It has been found that more thanone strand can be drawn in closely spaced relation through a pair ofcoacting high speed pulling wheels for deflection from a singledeflection unit 24 without snagging or otherwise causing a disturbancein continuity of control over the strands in their passage to thecollection zone. Each of two strands can be drawn through the pullwheels and imparted sufl icient kinetic energy to effect its deflectionfrom the unit 24 at speeds in the order ranging from 2000 feet perminute and up. By being allowed to pull more than one strand through asingle pair of pull wheels simultaneously, a mat of the resulting layerof strand deposited on the conveyor for a given speed of pull can bemade of finer texture with a greater number of interstices since it canbe arranged that strands of fewer number of filaments andcorrespondingly, strands of lesser diameter and greater yardage perpound, can be incorporated within a given time from a single formingposition. Under these conditions a mat layer of given weight has atexture of greater refinement than an equal weight mat of greaterdiameter strands. In being deflected from the unit 24, the two strandsare thrown as an inter-associated mass of continuous strands each ofwhich assumes a somewhat helical or swirled configuration and is thrownforwardly into the strand accumulation 33 in the collection zone.

Upon passage of the accumulation of strand between the overhangingconveyor 26 and the conveyor 35 upon which it is laid, the mass iscompressed into a more compacted relationship, but only in a temporarysense since upon release from between the overhanging conveyor, theaccumulation expands to a portion of its original thickness.

After. release from under the overhanging belt 26, the mass is subjectedto the forces of a series of gaseous jets,

tubular blower.32 extending across the width of the conveyor 35 and overthe mass already somewhat compacted. The tube 32 is oscillated in shortstroke vibratory manner over the full width of the mass in order tocause each of the jets to extend over a portion of the width of the matand correspondingly to be more effective in inter-knitting a portion ofthe width of the layer of material on the conveyor 35. The blower tube32 is oscillated by a drive motor 61 which drives a pulley 63 and aneccentric drive wheel 64 through a 'gear train in a gear box 62. A bar66 connects the eccentric drive wheel 64 with an arm 68 which isslidably mounted for horizontal reciprocation within a bearing block 69supported from a support channel 70.

The blower tube 32 can be oscillated across the conveyor at any of avariety of frequencies depending on the speed of movement of theconveyor 35 while the gas pressure in the tube 32 may be at any of anumber of magnitudes. If the spacing of the jet orifices in the tube 32is small, the amplitude and rate of the cyclic oscillation need not beas great as that if the spacing were large. By way of example withoutintention to quantitatively limit the invention, experience hasindicated that satisfactory results can be obtained by oscillating jetsspaced ap' proximately 5" apart across a 50 width of mat at 300 cyclesper minute with a 6" stroke. Correspondingly, if the jets were spaced 1"apart and the stroke is /2", the oscillatory action may be inthe rangeof 60 cycles per minute. Under these conditions, steam at a pressure of100 to 120 pounds per square inch has been found quite satisfactory inproducing the results desired, while air at a pressure of 70 to 100pounds per square inch is also quite satisfactory. Layers of mat in therange of thickness of from A2" to can be treated under the aboveconditions.

- For porous thats, the inter-knitting of fiber or filamentous portionsincorporated therein can be accomplished readily with lesser pressurebehind the gaseous jets than in mats of lesser porosity. Also, undergiven pressure conditions, the greater the porosity of the mat, thegreater is the thickness of mat which can be treated. Correspondingly,the greater the pressure behind the gaseous jets, the greater is thethickness of mats which given jets are capable of treating. The numberoflayers of mat which may be inter-knitted in this way again is notlimited since inter-knitting of layers can be accomplished as long aseach new top layer can be operated upon in such manner as to permitinter-knitting of the loops thereof with an immediately underlyinglayer.

It will also be understood that although a single longitudinal tubemechanism is shown for supply of gaseous jets operating against theupper surfaces of deposited layers of strand, jets may also be directedfrom under the foraminous conveyor against the bottom-most layer of maton the conveyor to cause inter-knitting of the bottom portions of themat with more interior portions thereof. In other words, when a singlelayer of mat is to be treated for integration thereof it may be treatedfrom both the upper and lower surfaces to cause the inter-knitting ofportions at both major surfaces with interior portions of the mat. 7

Although a multiplicity of aligned jets in a single row are shown hereinas being used to inter-knit fibrous matter, it will be understood thatmore than one row of jets may be traversed across a fibrous mass tocause its self integration. Also, a single jet of gas traversed across afibrous mass with sufficient rapidity will effect such integration.Still further, a plurality of jets in fixed nontraversing dispositionover such a mass, or a wide sheettype jet might be used to eliect thedesired result. A traversing jet, however, has in most instances beenfound preferable. The traversing action, it is believed, effects betterinterlacing of the several strand portions because of its lateralcomponent of force by reason of motion in 6 7 addition to its downwardcomponents. In this respect it is to be noted that the jets directedagainst the exposed surface of' a fibrous mass can be inclinedsomewhatfrom the perpendicular tov the exposed surface to provide additionallateral components of force against the mass.

FIGURE 3 illustrates a section of mat 31 indicating in a general mannerthe way in which strand portions of the mat are inter-knitted orinter-linked to effect a bonded relationship between closely spacedportions thereof to provide the mat integrity desired without need foradhesive bonding material.

Although the invention as thus far described has been described inrelation to formation of binderless mats of continuous strands andfibers, it will be understood that the principles of the invention arealso applicable to making of binderless mats of masses of discontinuousfibers.

Referring to FIGURE 4, a source of molten material such as a forehearth82 of a melting furnace supplies molten glass to a feeder 83 havingorificedt-ips 84 associated therewith from which streams of glass 85 areemitted. The glass emitted from the feeder orifices are subjected toforces of blasts of gas such as steam or air from a gaseous blower 86.The blower 86 is connected to a header 88 from which the gas such assteam or air under pressure is supplied to the blower. Glass whensubjected to the forces of such gas are effective in disrupting thematerial of the streams into discontinuous fibers which are thenintroduced into a hood 89 disposed below. Thehood provides a means forchannelling the fibers to a conveyor 95 located thereunder. The conveyor95 is a foraminous belt of chain mesh-type and has a suction chamber 90located under the collection zone within the hood 89.

Gases and fibers within the hood are drawn downwardly toward thecollection surface by reason of the reduced atmospheric pressure in theregion at the lower end of the hood. Fibers collected within the hoodare carried forwardly on the conveyorbelt as a mass 91. In being carriedforward, the mass 91 is conveyed under a gaseous blast source 92 fromwhich blasts or jets of gas are ejectedacross the width of .the conveyorand operate on the surface of the mat in the same manner as the jetsemitted from the tube 32 to cause an inter-entangling of the fibers ofthe mass so as to establish an integrity in the entire mass forproduction of a unitary mat. The jets are spaced along the length of thetube 92 across the width of the conveyor and are adapted to beingoscillated in the same manner as in the arrangement of FIGURE 2.Integration of the mass is similarly accomplished without binder and themass is imparted a stable dimensional character of thickness somewhatless than it had before being subjected to the forces of the jets. Inone sense it might be considered that the gaseous jets act as mechanicalpushers which pushsurface portions of the mat in inter-engaging lock-ingrelation as well as to the interior of the mass to effect aninter-knitting of the surface and interior portions of the mass.

A variety of fibers'and fiber mixtures may be formed into aninter-knitted self-integrated mat product according to the principles ofthe presently described process. Beside fibers of glass, fibers ofrayon, alginate fibers, superpolyamide fibers, polyvinyl fibers,polyvinylidene fibers, acrylonitrile fibers, protein fibers, or mineralfibers such as rock fibers and the like can be so treated.

FIGURE 5 illustrates another embodiment of the present invention inwhich a mat 101 is already formed and supplied from a roll and is passedover a conveyor 105 of foraminous-type having configurated apertures 111therein. The conveyor belt 105 is supported on rotatable rolls 109 and110 and is associated with overlying rollers 1% and 104 under which themat 101 is drawn and subsequently rolled into a roll-type package 106.The fibrous mat 101 is bonded together and has an integrity of its ownalready established without need for being subjected to further forcesof gaseous jets, but the mat is passed under a jet source such as atubular blower 102 from which jets of gas are blasted against thesurface of the mat to cause an embossment thereof by reason ofdepressions having been formed in the mat within the apertures 111 ofthe conveyor 105. In a sense, the mat is thus caused to take on theappearance of a series of configurated pock marks or pockets in itsupper surface as well as configurated embossments on the opposite side.In addition to subjecting the mat to the forces of the jets from thesource 162, a suction box 103 is provided under the conveyor to aid thejet source in imparting the depressions and embossments in the surfaceof the mat. The action of the suction chamber, in addition establishes amore intimate contact of the mat with the conveying belt and results inthe mat being carried forwardly more positively. The forward motion ofthe mat may be effected by synchronizing the roll-up by way of drivingthe roll 1% and the conveyor belt 105 by suitable conventional means notshown.

Thus, the principles of the present invention can be utilized to impartdecorative effects to the mats already formed as Well as to permitproduction of a binderless mat. Additionally, it is to be understoodthat the principles are applicable to production of a binderless mat ofdecorative character in that a mat may be produced as described abovehaving configurated depressions and corresponding embossments impressedtherein directly in the mat integration process. This is accomplishedmerely by providing configurations in the foraminous conveyor in thezone in which the binderless mat is formed by gaseous jets.

FZGURE 6 illustrates another conveyor which has star shaped aperturestherein so that depressions and embossmerits can be imparted to fibrousmats. It will be apparent from the foregoing that a wide variety ofdecorative configurations can be imparted to mats subjected to theforces of jets according to the present invention.

FIGURE 7 illustrates still another arrangement wherebydecorativeimpressions may be imparted to mats already formed. In this arrangementthe decorative patterning of the mat is effected by provision of thedesired configurated apertures in a drum. A bonded fibrous mat 121 isfed froma supply roll 120 over a feed roll 123 and is held against the.apertured surface of a rotating drum 125. Air, steam or other gas isdriven through the mat and surface of the drum 125 under the action offorces provided by a suction chamber 128 disposed in the interior of thedrum 125 below the area within which the forces of one or more gaseousblowers 122 are operating. An endless belt may be arranged to makecontact with the mat and to hold the mat against the surface of the drumthroughout the remainder of its distance of contact about thecircumference of the drum 125 until the mat is rewound. This isaccomplished by looping the endless belt 129 over a series of rolls 133arranged to hold the fabric snugly against the surface of the drum andto move in synchronism with the surface of the drum as it rotates. Thebonded mat 121 is introduced in between the endless fabric 129 and thedrum surface and moves forwardly over the drum surface until rewoundinto a shipping package 126. If the gas driven against the mass offibers is moist, however, the fabric may be passed through a zone of thedrum in which it is subjected to heat for drying pur- 8 poses beforebeing rewound. The heat can be supplied rom suitable means such as anelectric heater unit '132 located in a forward position along the drumcircumference. if the belt 129 is pervious, then'a gaseous blower may beused to supply the heat for. drying and a second suction zone might belocated on the side opposite to the belt from that on which the bloweris located to aid in the drawing of the hot gas through both the beltand drum.

The belt holding the bonded mat in contact with the drum surface may beof hardware cloth or other material having high tear strength and mayhave configurated apertures therein if desired to impart a desiredembossed configuration to the mat being treated.

Although there has been described herein, what at presout are consideredpreferred embodiments of the invention, various modifications of theinvention will be apparem to those skilled in the art and it is mydesire that the appended claims shall cover all modifications andarrangements which come within the scope and spirit of my invention.

I claim: a i

1. The method of imparting a decorative character to a porous fibroussheet comprising depositing a layer of fibrous sheet material on aforaminous' surface having patterned apertures therein, subjecting saidsheet material to the forcesv of at least one gaseous jet sufiicient tointerentangle fibers in said layer and depress the surface portions ofsaid layer immediately adjacent said foraminous surface within therecesses of said apertures, thereby to formembossments on said layer ofthe surface portions depressed in said apertures.

2. The method of producing a porous fibrous sheet of decorativecharacter comprising forming a multiplicity of fibers, distributing saidfibers as a layer of fibrous sheet material on a forarninous surfacehaving patterned apertures therein, subjecting said sheet material tothe forces of at least one gaseous jet sufiicient to interengage saidfibers in said layer and depress the surface portions of said layerimmediately adjacent said foraminous surface within the recesses of saidapertures, thereby to form embossments on said layer of the surfaceportion depressed in said patterned apertures.

3. The method of imparting a decorative character to a porous fibroussheet comprising passing a layer of the fibrous glass sheet material inintimate contact with a foraminous surface having patternedaperturestherein, subjecting said sheet material to the forces of gaseous jetssufficient to interemtangle the fibers in said layer and project thesurface portions of said layer immediately adjacent said foraminoussurface within the recesses of said apertures thereby formingembossments on said layer surface, and concomitantly drawing saidembossments within said apertures by establishment of a low pressurezone immediately under said forarninous surface in the areas in whichsaid jets act upon said layer, and then removing said interentangledembossed portions of the layer from said low pressure zone.

References Cited in the file of this patent UNITED STATES PATENTS2,302,020 Frederick Nov. 17, 1942 2,862,251 Kalwaites Dec. 2, 1958

1. THE METHOD OF IMPARTING A DECORATIVE CHARACTER TO A POROUS FIBROUSSHEET COMPRISING DEPOSITING A LAYER OF FIBROUS SHEET MATERIAL ON AFORAMINOUS SURFACE HAVING PATTERNED APERTURES THEREIN, SUBJECTING SAIDSHEET MATERIAL TO THE FORCES OF AT LEAST ONE GASEOUS JET SUFFICIENT TOINTERENTANGLE FIBES IN SAID LAYER AND DEPRESS THE SURFACE PORTIONS OFSAID LAYER IMMEDIATELY ADJACENT SAID FORAMINOUS SURFACE WITHIN THERECESSES OF SAID APERTURES, THEREBY TO FORM EMBOSSMENTS ON SAID LAYER OFTHE SURFACE PORTIONS DEPRESSED IN SAID APERTURES.